Help with Trigonometric functions in FreeCad Spreadsheet

[penneng]

OS: Windows 7
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.16131 (Git)
Build type: Release
Branch: releases/FreeCAD-0-18
Hash: 3129ae4296e40ed20e7b3d460b86e6969acbe1c3
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)

I get an "ERR" in cell F1 when I try to use the following trig cell formula in cell F1: formula in cell F1, "=atan(C5)", value in cell C5 is .333. What am I not understanding? Thanks for your help.

[openBrain]

Please attach your file. Here it works well.

[chrisb]

Works here as well. Is it possible that something with the locale is out of whack? You may try the following in C5:
0.333
0,333


OS: macOS High Sierra (10.13)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.18403 (Git)
Build type: Release
Branch: master
Hash: 0717b4fc23ef1db70964c3977d25e2fe46a739d1
Python version: 3.7.3
Qt version: 5.12.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/Germany (en_DE)